Along with Manoranjana, CBI sleuths arrested city-based entrepreneur Santanu Ghosh in connection with the scam.

Manoranjana and Ghosh were grilled by the CBI's Special Crime Branch in the satellite township of Salt Lake for hours before they were eventually arrested.

"Both the arrested people have been interrogated earlier but they not only failed to explain the facts but also allegedly concealed vital information and did not cooperate with the CBI," said a CBI officer.

"Their alleged involvement in criminal conspiracy with Saradha chief Sudipta Sen for personal gain of huge amounts running into crores of rupees by way of misappropriation of funds collected from innumerable poor investors and also cheating them have come during the ongoing investigation," the officer added.

The CBI had arrested Matang Sinh in January for his alleged complicity in the scam.

The CBI and the Enforcement Directorate had since 2014 been quizzing Manoranjana -- who along with many other high-profile names -- has been accused of complicity in the scam by Saradha group head and kingpin Sudipta Sen in his 2013 tell-all letter to the CBI.

Manoranjana, a former journalist, had allegedly sold her shares in an audio-visual channel to the Saradha Group.

She had also purportedly taken Sen to the lawyer-wife of a former union minister for settling a deal, Sen claimed in the letter.

Paul, who represents Krishnanagar Lok Sabha constituency in Nadia district, was quizzed about the Rose Valley group, as he was a former director in one of its firms.

In March, CBI sleuths, as part of a crackdown on Rose Valley, raided Paul's Kolkata residence.

Both Manoranjana and Ghosh will be presented before a city court on Thursday.